The most general form of the lighting equation uses both the vertex position and a vector that is normal to the object’s surface at that position; this is called the normal vector. Ideally, these normal vectors are captured or computed with the original model data, but in practice there are many models that do not include normal vectors.

Autodesk Inventor provides powerful API interface the access the model tessellation and visualization. This blog series attempt to explain how to use Inventor C++ API to get a triangulated geometry from Autodesk Inventor model for downward processing. Assembly document, part document and sheet bodies are covered as model geometry for tessellation. Tessellation data is stored along with feature information and BREP structure in CAD part and assembly file.